A primary file can be used to specify default build properties for software under development. A set of modified build properties may be stored in a supplemental file. The default build properties can be temporarily overridden with modified build properties for a given build, allowing freedom in the choice of build properties without proliferation of files used for the same purpose, which can be confusing. In addition, users can create new build commands for software under development, and associate the new commands with supplemental files. When the user invokes a new build command, the build process can override the default properties with the modified properties in the supplemental file, and then restore the defaults. Other advantages and features of the invention are described below.